The present invention relates to mining shovels, and in particular a snubber for a shovel dipper.
Mining rope shovels generally utilize a dipper for digging into a bank of material. The dipper has a dipper door on the bottom surface of the dipper that is rotatably connected by a door pin. After filling the dipper, the operator positions the dipper over a loading vehicle and triggers a latch mechanism to release the dipper door. Under the weight of the material in the dipper, the door swings down and away from the dipper body about the door pin. After the payload has been transferred to the loading vehicle, the operator then moves the dipper against the ground, forcing the door to rotate against the dipper body and causing the latch to lock the door. To prevent the dipper door from slamming against the dipper body when it is closed and to prevent the door from slamming against the loading vehicle when it is opened, a hydraulic snubber is coupled between the dipper door and dipper body to dampen rotation of the door. Generally, a snubber is coupled to each side of the dipper so that the dipper door rotates evenly and does not tilt to one side.
Hydraulic snubbers utilize an internal chamber filled with hydraulic fluid to resist movement of a paddle in one rotational direction, thereby dampening rotation of the paddle when the door opens or closes. Since conventional snubbers dampen rotation in only one direction (i.e., only when the door either opens or closes), a separate snubber must be configured for each side of the dipper. Because snubbers generally are subject to extreme forces, the seals in a hydraulic snubber must be able to withstand significant pressure in order to sufficiently dampen rotation of the dipper door and control the release of material.